Thanks for doing this comparison, even though it is not exactly scientific in nature. I have to agree with the others who prefer the X100s output – to me it the white balance and color generally is more accurate. Also, the shots where the X100s looks underexposed seem to either have had negative exposure comp dialed in (compared to the X100 shot) or were shot with a wider aperture, so lens vignetting probably played some part. All told, the difference is not really all that great. The X100 seems to generally end up with warmer colors, but if you prefer that look it's a pretty simple tweak in LR.